diff options
Diffstat (limited to 'compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp')
-rw-r--r-- | compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp new file mode 100644 index 000000000000..ef14fb704eed --- /dev/null +++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cpp @@ -0,0 +1,133 @@ +//===-- sanitizer_stacktrace.cpp ------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file is shared between AddressSanitizer and ThreadSanitizer +// run-time libraries. +//===----------------------------------------------------------------------===// + +#include "sanitizer_common.h" +#include "sanitizer_flags.h" +#include "sanitizer_stacktrace.h" + +namespace __sanitizer { + +uptr StackTrace::GetNextInstructionPc(uptr pc) { +#if defined(__sparc__) || defined(__mips__) + return pc + 8; +#elif defined(__powerpc__) || defined(__arm__) || defined(__aarch64__) + return pc + 4; +#else + return pc + 1; +#endif +} + +uptr StackTrace::GetCurrentPc() { + return GET_CALLER_PC(); +} + +void BufferedStackTrace::Init(const uptr *pcs, uptr cnt, uptr extra_top_pc) { + size = cnt + !!extra_top_pc; + CHECK_LE(size, kStackTraceMax); + internal_memcpy(trace_buffer, pcs, cnt * sizeof(trace_buffer[0])); + if (extra_top_pc) + trace_buffer[cnt] = extra_top_pc; + top_frame_bp = 0; +} + +// Sparc implemention is in its own file. +#if !defined(__sparc__) + +// In GCC on ARM bp points to saved lr, not fp, so we should check the next +// cell in stack to be a saved frame pointer. GetCanonicFrame returns the +// pointer to saved frame pointer in any case. +static inline uhwptr *GetCanonicFrame(uptr bp, + uptr stack_top, + uptr stack_bottom) { + CHECK_GT(stack_top, stack_bottom); +#ifdef __arm__ + if (!IsValidFrame(bp, stack_top, stack_bottom)) return 0; + uhwptr *bp_prev = (uhwptr *)bp; + if (IsValidFrame((uptr)bp_prev[0], stack_top, stack_bottom)) return bp_prev; + // The next frame pointer does not look right. This could be a GCC frame, step + // back by 1 word and try again. + if (IsValidFrame((uptr)bp_prev[-1], stack_top, stack_bottom)) + return bp_prev - 1; + // Nope, this does not look right either. This means the frame after next does + // not have a valid frame pointer, but we can still extract the caller PC. + // Unfortunately, there is no way to decide between GCC and LLVM frame + // layouts. Assume LLVM. + return bp_prev; +#else + return (uhwptr*)bp; +#endif +} + +void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top, + uptr stack_bottom, u32 max_depth) { + // TODO(yln): add arg sanity check for stack_top/stack_bottom + CHECK_GE(max_depth, 2); + const uptr kPageSize = GetPageSizeCached(); + trace_buffer[0] = pc; + size = 1; + if (stack_top < 4096) return; // Sanity check for stack top. + uhwptr *frame = GetCanonicFrame(bp, stack_top, stack_bottom); + // Lowest possible address that makes sense as the next frame pointer. + // Goes up as we walk the stack. + uptr bottom = stack_bottom; + // Avoid infinite loop when frame == frame[0] by using frame > prev_frame. + while (IsValidFrame((uptr)frame, stack_top, bottom) && + IsAligned((uptr)frame, sizeof(*frame)) && + size < max_depth) { +#ifdef __powerpc__ + // PowerPC ABIs specify that the return address is saved at offset + // 16 of the *caller's* stack frame. Thus we must dereference the + // back chain to find the caller frame before extracting it. + uhwptr *caller_frame = (uhwptr*)frame[0]; + if (!IsValidFrame((uptr)caller_frame, stack_top, bottom) || + !IsAligned((uptr)caller_frame, sizeof(uhwptr))) + break; + uhwptr pc1 = caller_frame[2]; +#elif defined(__s390__) + uhwptr pc1 = frame[14]; +#else + uhwptr pc1 = frame[1]; +#endif + // Let's assume that any pointer in the 0th page (i.e. <0x1000 on i386 and + // x86_64) is invalid and stop unwinding here. If we're adding support for + // a platform where this isn't true, we need to reconsider this check. + if (pc1 < kPageSize) + break; + if (pc1 != pc) { + trace_buffer[size++] = (uptr) pc1; + } + bottom = (uptr)frame; + frame = GetCanonicFrame((uptr)frame[0], stack_top, bottom); + } +} + +#endif // !defined(__sparc__) + +void BufferedStackTrace::PopStackFrames(uptr count) { + CHECK_LT(count, size); + size -= count; + for (uptr i = 0; i < size; ++i) { + trace_buffer[i] = trace_buffer[i + count]; + } +} + +static uptr Distance(uptr a, uptr b) { return a < b ? b - a : a - b; } + +uptr BufferedStackTrace::LocatePcInTrace(uptr pc) { + uptr best = 0; + for (uptr i = 1; i < size; ++i) { + if (Distance(trace[i], pc) < Distance(trace[best], pc)) best = i; + } + return best; +} + +} // namespace __sanitizer |